Almost 800 years later, a geologist named Jack Hartung concluded that what the monks saw was actually the formation of the Girodano Bruno crater, a well-known landmark on the lunar surface.

The timing of the monks' sighting also coincided with the annual Taurid meteor shower. Some believe that a meteor from the Taurids was also responsible for the Tunguska event.

Critics of the the connection between the monks' sighting and the crater point to the fact that an impact of that size on the Moon should have been followed by a significant increase in shooting stars seen from the Earth, but no such spike shows up in the historical record.